Capturing a still image and video image during a single exposure period

BACKGROUND

0001Digital cameras are increasingly popular and technology advances have resulted in these cameras having the capability to capture video data as well as high resolution still images. A digital camera captures an image (e.g., a subject, scene, or view) in elemental portions and generates an electronic signal that is representative of the subject, scene, or view. Unlike conventional film cameras that use a photo-responsive film as the image capturing medium, digital cameras typically use one or more charge coupled device (CCD) integrated chips. The CCD chips are configured to receive light reflecting from the photographic subject and to convert the reflected light into a digital signal representative of the captured image.

0002Many of these digital cameras can operate in a first capture mode for capturing high resolution still images (e.g., typically 2.1 mega pixels or greater), and operate in a second capture mode for capturing low resolution video data (e.g., typically 0.3 mega pixels or less). Because of the two modes of operation, a user desiring to capture both video images and high resolution still images of a scene must switch modes, likely resulting in the shot being missed.

0003Two modes are utilized for a variety of reasons. In the second capture mode, the digital camera may be able to capture multiple still images per second (e.g., 30 frames per second), usually in a low resolution, which amounts to video data. Operating in the first capture mode, the digital camera can capture high resolution still images. Because of the high resolution, these still images cannot be processed at the rate of the video images captured in the second mode. Accordingly, different modes are used.

SUMMARY

0004According to an embodiment, a method for capturing video and still images comprises steps of exposing at least one sensor for a first period of time to incident light producing an image; generating video data from the exposed at least one sensor prior to the end of the first period of time wherein the video data is representative of the image; and generating still image data from the exposed at least one sensor wherein the still image data is representative of the image.

0005According to another embodiment, an imaging apparatus is operable to substantially simultaneously capture still image data and video data. The imaging apparatus includes an optical system capturing incident light producing an image and an integrated circuit including at least one sensor receiving the incident light and substantially simultaneously generating the still image data and the video data within an exposure window. The imaging apparatus also includes a controller transmitting signals to the integrated circuit for controlling the generation of the still image data and the video data.

0006According to yet another embodiment, an integrated circuit is operable to substantially simultaneously generate still image data and video data. The integrated circuit comprises at least one sensor receiving incident light during an exposure window and an exposure period within the exposure window. The at least one sensor is operable to output a first set of pixels substantially at an end of the exposure period and output a second set of pixels substantially at an end of the exposure window. A controller is operable to bin at least some of the first set of pixels, wherein the controller generates video data from the binned pixels and generates still image data from at least some of the second set of pixels.

0007According to yet another embodiment, an imaging apparatus comprises means for exposing at least one sensor for a first period of time to incident light producing an image; means for generating video data from the exposed at least one sensor prior to the end of the first period of time wherein the video data is representative of the image; and means for generating still image data from the exposed at least one sensor wherein the still image data is representative of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1</figref> illustrates an imaging system, according to an embodiment;

<figref idref="DRAWINGS">FIG. 2</figref> illustrates the integrated circuit imaging device shown in the imaging system of <figref idref="DRAWINGS">FIG. 1</figref>, according to an embodiment;

<figref idref="DRAWINGS">FIG. 3</figref> illustrates multiple exposure windows, according to an embodiment; and

<figref idref="DRAWINGS">FIG. 4</figref> illustrates a flow diagram of an exemplary method for capturing still images and video, according to an embodiment.

DETAILED DESCRIPTION

0012<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of an imaging system <b>100</b>, according to an embodiment. The imaging system <b>100</b> may be utilized in an imaging device, such as digital camera, camcorder or any image device that may capture, process or otherwise use multimode image data. The imaging system <b>100</b> includes an optical system <b>130</b> that channels incident light representative of an image to photo-receptive sensors on an integrated circuit <b>10</b>. The sensors may include complementary metal oxide (CMOS) sensors or other sensors that are capable of nondestructive readouts.

0013A CCD sensor is a charge storage and transfer device. The charge represents the light intensity falling on a pixel at the instant of readout (i.e., when the charge is transferred). The charge can only be transferred from the CCD sensor one time (i.e., a destructive readout). Instead, a CMOS sensor, for example, is able to readout image data multiple times. That is, the image data can be output from the CMOS sensor and the CMOS sensor may continue to store the image data until it is reset. Therefore, a CMOS sensor array is capable of nondestructive readouts, which enables the system <b>100</b> to substantially simultaneously capture video and still images as described in detail below.

0014A system controller <b>122</b> may transmit timing signals to the integrated circuit <b>10</b> for controlling capture of images by the sensors on the integrated circuit <b>10</b>. The system controller <b>122</b> may include one or more processors, processing circuitry, such as ASIC's, or any reasonably suitable combination thereof. A user may interact with the system controller <b>122</b> through a user interface <b>132</b>.

0015The integrated circuit <b>10</b> generates digital image data (e.g., video and/or still images), which is output to a buffer <b>114</b>. The integrated circuit <b>10</b> is capable of performing binning. As is known in the art, binning comprises summing pixels, which can lighten a dark image to improve image quality.

0016According to an embodiment, the system <b>100</b> is operable to simultaneously capture video data and still image data for generating a multimode stream of image data. Video data, for example, may include a stream of low resolution still images (e.g., video frames) and still image data may include still images typically having a higher resolution than the video data.

0017As described in co-pending U.S. patent application Ser. No. 10/304,947, herein incorporated by reference in its entirety, the system controller <b>122</b> may retrieve the multimode stream of image data from the buffer <b>114</b> (e.g., a first-in-first-out buffer) and output the multimode stream of image data to a local storage <b>128</b> and/or a communication interface <b>124</b>. The system controller <b>122</b> may filter still image data from the multimode stream unless a user event, which may include shutter activation or another event, is detected. If a user event is detected, still image data retrieved from the buffer <b>114</b> may be transmitted to the local storage <b>128</b> and/or the communication interface <b>124</b>. The buffer <b>114</b>, for example, may store at least 3 seconds of image data from the multimode stream. The buffer size, however, can be larger or smaller depending on the requirements of the system <b>100</b>. Furthermore, by using the buffer <b>114</b>, still image data corresponding to a detected user event (e.g., 1.5 seconds of still image data before and after the detected user event) may be retrieved such that a user does not miss a shot. For example, the shutter is activated by the user. The system controller <b>122</b> receives 1.5 seconds of still image data before and after the shutter activation from the buffer <b>114</b>. Then, the user may select a desired still image from the still image data. Therefore, still image data is stored only when desired by a user, which conserves the limited storage in the system <b>100</b>, and a sufficient amount of still image data may be stored to prevent a user from missing a shot.

0018Transmission of the image data to an external processing system may be accomplished using the communication interface <b>124</b>. For instance, as a digital camera, the system <b>100</b> may include a communication interface that implements a computer peripheral bus standard such as universal serial bus (USB) or Institute of Electronic and Electrical Engineers (IEEE) 1394 specification (1995). The local storage <b>128</b> may be of the non-volatile variety (e.g., a removable memory card, a rotating magnetic disk device, or other suitable memory device for permanent storage of digital image data).

0019Although not shown, the system <b>100</b> may include image processing circuitry including hardwired logic and/or a programmed processor that performs a variety of functions, including preparing digital image data based on sensor signals generated by the integrated circuit <b>10</b> for storage or transmission. Post processing may further include effects processing (e.g., fades, dissolves, overlays, etc.) and compression. Other instances of well-known structures, interfaces, and processes have not been shown in detail in order not to unnecessarily obscure the description of the embodiments.

0020According to an embodiment, <figref idref="DRAWINGS">FIG. 2</figref> illustrates the integrated circuit <b>10</b> formed from a CMOS process on a chip having at least one CMOS sensor array <b>12</b>, a controller unit <b>16</b> and an input/output (I/O) port <b>18</b>. The sensor array <b>12</b> may include a grid of individual CMOS light sensing picture elements (not shown) sensing an amount of light intensity illuminating the sensing elements, such as from the images produced thereon by the optical system <b>130</b> of <figref idref="DRAWINGS">FIG. 1</figref>. The sensor array <b>12</b> is configured to output analog signals representative of the amount of light intensity on the sensing elements to the controller <b>16</b> along an analog signal connection bus <b>20</b>. Depending upon the configuration, analog signals from sensor elements in the array <b>12</b> may be output simultaneously in parallel, output one at a time in series, or output row-by-row or column-by-column, etc.

0021The controller unit <b>16</b> includes analog-to-digital (A/D) circuitry, not shown, for converting analog signals received from the sensor array <b>12</b> to digital signals. In addition, the controller unit <b>16</b> contains circuitry for processing the received signals. The digital signals are routed along a digital bus line <b>22</b> to digital I/O port <b>18</b> for output. The controller unit <b>16</b>, depending upon the configuration, can perform one of a wide variety of image processing operations including, for example, pattern recognition operations, filtering operations, Fourier transform operations, and the like. Resulting digital signals are output from circuit <b>10</b> through digital I/O port <b>18</b>. Depending upon the implementation, the content and format of the digital signals output by the controller unit <b>16</b> may differ.

0022According to an embodiment, the integrated circuit <b>10</b> is capable of simultaneously capturing still image data and video data by performing pixel binning and using multiple exposure times. The integrated circuit <b>10</b> may include a known CMOS integrated circuit capable of performing binning. For example, FOVEON, provides a CMOS circuit with binning capability. As is known in the art, binning comprises summing pixels, which can lighten a dark image to improve image quality.

0023The system <b>100</b> uses an exposure window and binning techniques for capturing high resolution still images and video substantially simultaneously. <figref idref="DRAWINGS">FIG. 3</figref> illustrates multiple exposure windows <b>310</b>, <b>320</b> and <b>330</b>, according to an embodiment. In the exposure window <b>310</b>, binning is performed by the circuit <b>10</b> (e.g., the controller <b>16</b> in the integrated circuit <b>10</b> executing firmware) from the start of the video signal frame capture <b>312</b> to the end of a predetermined, shortened, exposure time <b>314</b> (e.g., 1/90 of a second). At substantially the point <b>314</b> in the exposure window <b>310</b>, a video frame is generated by the circuit <b>10</b>, prior to an end <b>316</b> of the exposure window <b>310</b>. A digital still image is readout at the end of the exposure window <b>316</b> (e.g., ranging from 1/24 to 1/30 of a second, inclusive). The sensor array <b>112</b> may then be reset, and video frames and still images may continue to be captured during exposure windows <b>320</b>, <b>330</b>, etc.

0024Exposure windows <b>320</b> and <b>330</b> are substantially similar to the exposure window <b>310</b>. Also, if binning is not performed (e.g., when still images are not produced), then a readout is not performed prior to end of the exposure window. In addition, the integrated circuit I/O may include a device (e.g., a CMOS integrated circuit) operable to perform a nondestructive readout prior to an end of an exposure window.

0025<figref idref="DRAWINGS">FIG. 4</figref> is a flow diagram of a method <b>400</b> for simultaneously capturing video and still images according to an embodiment. In step <b>410</b>, the system <b>100</b> is set to binning mode, such that the imaging device may perform binning for captured images. In step <b>420</b>, the system <b>100</b> begins exposure of the circuit <b>10</b> to incident light to capture a video frame, such as when the exposure window <b>310</b> is started. This step and the step <b>410</b> may be initiated by a user.

0026In step <b>430</b>, binning is performed on pixels (i.e., data produced by light sensing picture elements) generated by the circuit <b>10</b> for a predetermined period of time within the exposure window. In step <b>440</b>, video data, such as a video frame, is output by the circuit <b>10</b> substantially at the end of the predetermined period of time. The pixels are generated, for example, by the CMOS sensor array <b>12</b> of the circuit <b>10</b> of <figref idref="DRAWINGS">FIG. 2</figref>.

0027In step <b>450</b>, still image data is output by the circuit <b>10</b> substantially at the end of the exposure window. For example, binning is stopped at the end of the predetermined period of time. The CMOS sensor array <b>12</b> outputs pixels again substantially at the end of the exposure window for generating still image data. In step <b>460</b>, the sensor array <b>12</b> in the circuit <b>10</b> is reset to capture more video frames and/or still images. Steps <b>420</b>–<b>460</b> may be repeated to continue to capture video and still images.

0028It will be apparent to one of ordinary skill in the art that the method <b>400</b> is subject to many alternatives, modifications and variations without departing from the spirit and scope of this embodiment of the method <b>400</b>. For example, steps <b>420</b>–<b>430</b> as well as steps <b>440</b>–<b>450</b> may be performed substantially simultaneously. These and other variations will be apparent to one of ordinary skill in the art.